Substrate treatment device

According to one embodiment, a substrate treatment device includes a placement stand configured to rotate the substrate, a cooling part configured to supply a cooling gas into a space between the placement stand and the substrate, a first liquid supplier configured to supply a first liquid on a surface of the substrate, a second liquid supplier configured to supply a second liquid on the surface, and a controller controlling rotation of the substrate, supply of the cooling gas, the first and second liquids. The controller performs a preliminary process of supplying the second liquid on the surface, and supplying the cooling gas into the space, a liquid film forming process by supplying the first liquid toward the surface after the preliminary process, a supercooling process of the liquid film on the surface, and a freezing process of at least a part of the liquid film on the surface.